Buggy code:
public class TestFieldsReader extends LuceneTestCase { private RAMDirectory dir = new RAMDirectory ( ) ; private Document testDoc = new Document ( ) ; private FieldInfos fieldInfos = null ; private static final String TEST_SEGMENT_NAME = "_0" ; public TestFieldsReader ( String s ) { } protected void setUp ( ) throws Exception { } public void test ( ) throws IOException { } public void testLazyFields ( ) throws Exception { } public void testLazyFieldsAfterClose ( ) throws Exception { } public void testLoadFirst ( ) throws Exception { } public void testLazyPerformance ( ) throws Exception { } public void testLoadSize ( ) throws IOException { } private void assertSizeEquals ( int size , byte [ ] sizebytes ) { } public static class FaultyFSDirectory extends Directory { FSDirectory fsDir ; public FaultyFSDirectory ( File dir ) throws IOException { } public IndexInput openInput ( String name ) throws IOException { } public String [ ] list ( ) throws IOException { } public String [ ] listAll ( ) throws IOException { } public boolean fileExists ( String name ) throws IOException { } public long fileModified ( String name ) throws IOException { } public void touchFile ( String name ) throws IOException { } public void deleteFile ( String name ) throws IOException { } public void renameFile ( String name , String newName ) throws IOException { } public long fileLength ( String name ) throws IOException { } public IndexOutput createOutput ( String name ) throws IOException { } public void close ( ) throws IOException { } } private static class FaultyIndexInput extends BufferedIndexInput { IndexInput delegate ; static boolean doFail ; int count ; private FaultyIndexInput ( IndexInput delegate ) { } private void simOutage ( ) throws IOException { } public void readInternal ( byte [ ] b , int offset , int length ) throws IOException { } public void seekInternal ( long pos ) throws IOException { } public long length ( ) { } public void close ( ) throws IOException { } public Object clone ( ) { } } public void testExceptions ( ) throws Throwable { String tempDir = System . getProperty ( "java.io.tmpdir" ) ; if ( tempDir == null ) throw new IOException ( "java.io.tmpdir<seq2seq4repair_space>undefined,<seq2seq4repair_space>cannot<seq2seq4repair_space>run<seq2seq4repair_space>test" ) ; File indexDir = new File ( tempDir , "testfieldswriterexceptions" ) ; try { Directory dir = new TestFieldsReader . FaultyFSDirectory ( indexDir ) ; IndexWriter writer = new IndexWriter ( dir , new WhitespaceAnalyzer ( ) , true , MaxFieldLength . LIMITED ) ; for ( int i = 0 ; i < 2 ; i ++ ) writer . addDocument ( testDoc ) ; writer . optimize ( ) ; writer . close ( ) ; <START_BUG> IndexReader reader = IndexReader . open ( dir ) ; <END_BUG> TestFieldsReader . FaultyIndexInput . doFail = true ; boolean exc = false ; for ( int i = 0 ; i < 2 ; i ++ ) { try { reader . document ( i ) ; } catch ( IOException ioe ) { exc = true ; } try { reader . document ( i ) ; } catch ( IOException ioe ) { exc = true ; } } assertTrue ( exc ) ; reader . close ( ) ; dir . close ( ) ; } finally { _TestUtil . rmDir ( indexDir ) ; } } }

Fix:
IndexReader reader = IndexReader . open ( dir , true ) ;